EVAPOTRANSPIRATION OF TWO GERBERA JAMESONII CULTIVARS IN HYDROPONICS: ADJUSTMENT OF MODELS FOR GREENHOUSES

L. Mascarini, O.S. Delfino, F. Vilella
Commercial production of Gerbera jamesonii for cut flowers production has an outstanding level worldwide. The introduction of new irrigation systems and cultivation technologies, like hydroponics, carried out by the growers, makes necessary that the hydric requirements of the crop are known for the system to be efficient. The objective of this work is to determine the water consumption of two Gerbera cultivars in hydroponics, Testarossa (A) and Nevada (B), by adjusting current use models, for the area of influence of Buenos Aires city, during spring, summer and autumn seasons. The test was carried out in a metal structure greenhouse with polyethylene cover. Plants were placed in plastic bags with perlite substrate and drip irrigation. Water consumption by the plants was evaluated as the difference between the water added to each growth bag and the water drained on trays, so as to determine the crop's evapotranspiration (Etc). With the data registered in the greenhouse regarding temperature, relative humidity, cloudiness, and radiation, potential or reference evapotranspiration (Eto) was determined applying current use formulae like Blanney-Criddle and Penman-Monteith modified by FAO. This was established by Doorenbos and Pruitt, 1974, the crop coeficient Kc was determined, Etc/Eto=Kc, for each of the formulas that were used. The relation between Eto and Kc that determines the crop's evapotranspiration (Etc) is selected when it best adjusts to the measured consumption. To analyze the data, variance and regression analysis were applied with the procedures ANOVA, REG and CORR of the SAS program (v 6.12; SAS, INST. INC. CARY).
The Penman-Monteith method modified by FAO for the calculation of Eto was detected as the theoretical model that adjusts best to water consumption measured in the greenhouse (correlation coefficient: 96,7%; p<0.01) with the least residual standard error (ROOT MSE: 0.48), during the seasons considered.
Mascarini, L., Delfino, O.S. and Vilella, F. (2001). EVAPOTRANSPIRATION OF TWO GERBERA JAMESONII CULTIVARS IN HYDROPONICS: ADJUSTMENT OF MODELS FOR GREENHOUSES. Acta Hortic. 554, 261-270
DOI: 10.17660/ActaHortic.2001.554.27
https://doi.org/10.17660/ActaHortic.2001.554.27
soilless culture, irrigation systems, crop coefficient, protected crops, perlite
English

Acta Horticulturae